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Biomedical subjects

Q Gao

Publications and source records attributed to Q Gao.

At least 109 records · Page 6Linked to original sources
PubMed1999

[The value of nasal endoscopy in the resection of upper and posterior nasal septum deviation].

OBJECTIVE: In order to find a safe, reliable and satisfying technique to treat the upper and posterior nasal septum deviation. METHOD: Performing the resection of the upper and posterior nasal septum deviation under nasal endoscopy, comparing this new method with the traditional one and discussing the safety and long-term curative effect of this new method. RESULT: The observation of the outcome of 109 patients undergoing this operation after 1-50 months postoperation shows that this technique can resect the upper and posterior deviation safely and completely, improve the nasal respiratory and olfactory function and reduce the occurrence of nasal cavity adhesion and the recurrence of nasal polyp and sinusitis. CONCLUSION: Performing the resection of the upper and posterior nasal septum deviation under nasal endoscopy is a good method for popularizing to clinician.

Adult↗
PubMed1999

[Studies on detection of Plasmodium falciparum and Plasmodium vivax in blood samples by multiplex polymerase chain reaction].

AIM: To establish a sensitive and specific PCR-based method to detect Plasmodium falciparum and P. vivax in blood samples in a single amplification reaction. METHODS: Malaria parasite DNA in blood was amplified by the multiplex polymerase chain reaction using two sets of primers derived from the P. f. moderately-repetitive DNA sequence and COIII gene of P.v. RESULTS: A 206-bp product for P. f. and a 370-bp product for P.v. were amplified by multiplex PCR, being able to detect parasitemia level as low as 5 x 10(-7) for P. f. and 1.02 x 10(-6) for P. v. and having no cross-reaction with human leucocyte DNA. A total of 783 blood samples on the filter paper collected from patients attending to malaria clinics in malaria endemic areas were detected. The positive rate of multiplex PCR was 85.8%, the misdiagnosis rate was 0, and the under-diagnosis rate was 0.1%, while these three rates of microscopic examination were 84.9%, 3.1% and 1.0%, respectively. The concordance between the two methods was 95.8%. CONCLUSION: The multiplex PCR method made the malaria detection more sensitive and specific than the microscopic examination and should be suitable for the diagnosis of malaria in mixed endemic areas, large-scale epidemiological studies, follow-up of drug treatment and donor blood screening.

Animals↗
PubMed1999

[Clinical use of nasal airflow measurement in septoplasty].

OBJECTIVE: To discuss the clinical use of nasal airflow measurement in septoplasty. METHOD: After nasal decongestion, 21 patients's nasal airway resistance and nasal airflow were evaluated by anterior rhinomanometry before and after submucous resection of nasal septum. RESULT: The amount of nasal airflow asymmetry could show nasal respiratory function better than nasal airway resistance does, the patients with absolute amount of nasal airflow asymmetry greater than 50% had bad postoperative outcome, patients' satisfication with operation was significantly correlated with the presence of post-operative symmetrical nasal airflow. CONCLUSION: The amount of nasal airflow asymmetry can serve as an indicator of patient selection, outcome evaluation and prognosis in nasal septum deviation.

Adult↗
PubMed1999

[Clinical and bacteriology observation on intraoperation usage of tarivid otic solution in treatment of chronic otitis media with cholesteatoma].

OBJECTIVE: To determine the effect and safety of Tarivid (oflorxacin) otic solution used during the operation in treatment for chronic otitis media with cholesteatoma. METHOD: 42 patients were divided into two groups. In Tarivid group, 23 patients' operative cavities were soaked with 0.3% Tarivid, while other 19 patients' operative cavities in boric acid group were soaked with 4% boric acid during the open mastoidectomy with tympanoplasty. RESULT: The recovery rate was 82.6% and 50% respectively. There was significant difference between two groups (P < 0.05). No side effect was observed. CONCLUSION: It shows that using Tarivid otic solution in the operation can improve the outcome of the operation and has high security.

Adult↗
PubMed1999

[Microwave therapy of radiotherapeutical choanal atresia under nasal endoscope].

OBJECTIVE: In order to know efficacy of microwave to treat the secondary choanal atresia under nasal endoscope. METHOD: Three patients suffering from membranous choanal atresia due to radiotherapy of nasopharyngeal carcinoma (NPC) were treated by microwave under nasal endoscope. RESULT: Satisfing recoveries were accomplished in all patients and no relapse was found within the 7-13 months' follow-up. CONCLUSION: This method has many advantages, such as: processing available under local anesthesia without incision, mild damage to normal tissues, clear operation visual field, less hemorrhage and postoperative pain, complete coagulation and gasification of atresic membrane, no need of postoperative dilation and stable therapeutical effect.

Adult↗
PubMed1999

[Establishment of a microbial assay for screening anti-human immunodeficiency virus type-1 protease inhibitors].

OBJECTIVE: This study was to establish a microbial assay of human immunodeficiency virus type-1 protease (HIV-1 PR) activity for screening anti-HIV PR inhibitors. METHODS: A 24 bp synthetic oligonucleotide fragment that encodes the HIV-1 PR recognition sequence was inserted into the tetr gene of pBR322 (mtetr). Escherichia coli containing HIV-1 PR expression vector-pPOLO was transformed with pACYC184M containing modified mtetr gene. The transformant could express both HIV-1 PR and the modified Tet protein. RESULTS: The growth of engineered E. coli was prevented in the presence of tetracycline because the resistance Tet protein was degraded by HIV-1 PR. However inhibition of the HIV-1 PR restored tetracycline resistance. 31 chemical synthetic compounds were tested by the microbial assay. CONCLUSIONS: A microbial assay method of HIV-1 PR activity was established through a engineered E. coli. 5 mumol/L saqunavir-a special HIV-1 PR inhibitor showed inhibitory effect on the engineered E. coli. That means this model could be used as a initial screening model for anti-HIV PR agents.

Escherichia coli↗
PubMed1999

[Changes in nasal airway resistance before and after endoscopic sinus surgery].

OBJECTIVE: To study the influence of endoscopic sinus surgery(ESS) on nasal airway resistance (NAR) and to analyze the relationship between NAR and nasal airflow sensation. METHODS: The NAR and nasal airflow sensation were measured with anterior rhinomanometry and visual analogous scale test (VAS) in 42 patients (50 sides) before and after the ESS. RESULTS: NAR decreased significantly after the operation. The change rates in NAR before and after the decongestion were (55.71 +/- 13.90)% and (24.32 +/- 8.73)%, respectively, and there was a significant difference (P < 0.05). The pathological increase in NAR correlated well with subjective sensation of the patients (P < 0.05). CONCLUSION: The improvement of nasal functions by ESS is not due to the alteration of the anatomic structure of the nasal cavity, but to the amelioration of mucosal edema. The rhinomanometry can be used as a useful clinical tool in determining nasal patency.

Adolescent↗
PubMed1998

A matrix for DNA separation: genotyping and sequencing using poly(vinylpyrrolidone) solution in uncoated capillaries.

We report a new sieving matrix for DNA separation based on commercially available poly(vinylpyrrolidone). The new sieving matrix has a very low viscosity at moderate concentrations, e.g., 27 cP at 4.5%. Its excellent self-coating property can reduce electroosmotic flow to a negligible level. Column regeneration between runs is very simple and effective. Successful separations were achieved in uncoated capillaries. For genotyping, we show that D1S80 and amelogenin sex determination system can be baseline separated as double-stranded DNA, and vWF, TH01, TPOX, and CSF1PO short tandem repeats can be separated with single-base resolution as single-stranded DNA in this new matrix. Sequencing of M13mp18 showed good resolution up to 500 bases in a solution of high-molecular-weight fraction extracted from commercially available PVP. The feasibility of adaptation to a multicapillary array system is discussed.

Amelogenin↗
PubMed1998

MR image-guided portal verification for brain treatment field.

PURPOSE: To investigate a method for the generation of digitally reconstructed radiographs directly from MR images (DRR-MRI) to guide a computerized portal verification procedure. METHODS AND MATERIALS: Several major steps were developed to perform an MR image-guided portal verification procedure. Initially, a wavelet-based multiresolution adaptive thresholding method was used to segment the skin slice-by-slice in MR brain axial images. Some selected anatomical structures, such as target volume and critical organs, were then manually identified and were reassigned to relatively higher intensities. Interslice information was interpolated with a directional method to achieve comparable display resolution in three dimensions. Next, a ray-tracing method was used to generate a DRR-MRI image at the planned treatment position, and the ray tracing was simply performed on summation of voxels along the ray. The skin and its relative positions were also projected to the DRR-MRI and were used to guide the search of similar features in the portal image. A Canny edge detector was used to enhance the brain contour in both portal and simulation images. The skin in the brain portal image was then extracted using a knowledge-based searching technique. Finally, a Chamfer matching technique was used to correlate features between DRR-MRI and portal image. RESULTS: The MR image-guided portal verification method was evaluated using a brain phantom case and a clinical patient case. Both DRR-CT and DRR-MRI were generated using CT and MR phantom images with the same beam orientation and then compared. The matching result indicated that the maximum deviation of internal structures was less than 1 mm. The segmented results for brain MR slice images indicated that a wavelet-based image segmentation technique provided a reasonable estimation for the brain skin. For the clinical patient case with a given portal field, the MR image-guided verification method provided an excellent match between features in both DRR-MRI and portal image. Moreover, target volume could be accurately visualized in the DRR-MRI and mapped over to the corresponding portal image for treatment verification. The accuracy of DRR-MRI was also examined by comparing it to the corresponding simulation image. The matching results indicated that the maximum deviation of anatomical features was less than 2.5 mm. CONCLUSION: A method for MR image-guided portal verification of brain treatment field was developed. Although the radiographic appearance in the DRR-MRI is different from that in the portal image, DRR-MRI provides essential anatomical features (landmarks and target volume) as well as their relative locations to be used as references for computerized portal verification.

Brain Neoplasms↗
PubMed1998

Role of the transcription factor Sox-2 in the expression of the FGF-4 gene in embryonal carcinoma cells.

It has been shown previously that the FGF-4 gene is regulated by a powerful downstream enhancer in embryonal carcinoma (EC) cells. This enhancer contains an essential HMG motif; however, the transcription factor that binds to the HMG motif in EC cells has not been determined definitively. In earlier studies, this HMG motif was shown to bind a heat-stable, redox-insensitive factor expressed by F9 EC cells. Others have proposed that the transcription factor Sox-2 binds to the FGF-4 enhancer HMG motif. In this study, we demonstrate that the N-terminal half of Sox-2, which contains the DNA binding domain, binds to the FGF-4 enhancer HMG motif and we show that this binding is unaffected by heat and oxidation. In addition, we employed two experimental approaches to demonstrate that Sox-2 regulates the transcription of the FGF-4 gene in EC cells. As part of these studies, an expression plasmid that codes for a dominant-negative form of Sox-2 was used in transient expression assays. In other experiments, a Sox-2 antisense expression plasmid was used. When co-transfected into F9 EC cells along with an FGF-4 promoter/reporter gene construct, each expression plasmid caused a significant reduction in reporter activity. Our studies also demonstrate that Sox-2 affects the expression of the FGF-4 gene in the multipotent EC cell line, P19. Taken together, these studies argue strongly that Sox-2 plays an important role in the expression of the FGF-4 gene in vivo.

Animals↗
PubMed1998

CD4 regulatory cells in immune tolerance.

We have used the classic model of neonatal tolerance to investigate the hypothesis that acquired tolerance depends on the generation of regulatory CD4 cells. Injection of neonatal BALB/c mice with semi-allogeneic CAF1 (BALB/c X A/J) spleen cells induces antigen-specific tolerance (TOL) in 80% of mice. TOL mice accept fully allogeneic A/J skin grafts for >60 days. TOL mice show diminished Th1 CD4 and CD8 cell immunity against A/J in vitro. In contrast, TOL mice show increased levels of anti-A/J Th2 CD4 responses. Thus tolerance is associated with the inhibition of Th1 CD4 and TC1 CD8 responses and the enhancement of Th2 CD4 responses. Because of this relationship, we hypothesized that regulatory Th2 CD4 cells in TOL mice maintain tolerance by blocking activation of A/J-reactive TC1-CD8 cells. Using in vitro BrdU assays to measure CD8 proliferation within unfractionated cell cultures, we showed that CD8 cells from TOL mice proliferate normally to exogenous interleukin-2 (IL-2) but fail to proliferate in response to A/J cells. The addition of exogenous IL-2 does not restore CD8 proliferation to A/J, ruling out simple CD8 cell anergy. However, when CD4 cells are depleted from the cultures, IL-2 could restore the ability of A/J-reactive CD8 cells to proliferate and to secrete IFN-gamma. Thus CD4 cells from TOL mice inhibit IL-2 rescue of "anergic" A/J-reactive CD8 cells. The results demonstrate a novel link between two major mechanisms of tolerance, immunoredirection and anergy.

Animals↗
PubMed1998

Conjugates of Tremella polysaccharides with microbeads and their TNF-stimulating activity.

A mannan (A) and a heteroglycan (D) were prepared by partial acidic hydrolysis of T3, a major polysaccharide fraction of the fungus Tremella fuciformis Berk. Methylation analysis of A and D showed that they contained a 1-->3 linked mannosyl main chain, to which were linked different side chains at position 2, 4, or 6 of the mannosyl residues. A and D were conjugated to albumin microbeads (AM) by reductive amination. The conjugates showed significant cytokine-stimulating activity in vitro whereas unconjugated AM had no activity. Not conjugated A and D showed cytokine-stimulating activity only in about 100 times higher concentrations.

Basidiomycota↗
PubMed1998

Targeting gene expression to the head: the Drosophila orthodenticle gene is a direct target of the Bicoid morphogen.

The Bicoid (Bcd) morphogen establishes the head and thorax of the Drosophila embryo. Bcd activates the transcription of identified target genes in the thoracic segments, but its mechanism of action in the head remains poorly understood. It has been proposed that Bcd directly activates the cephalic gap genes, which are the first zygotic genes to be expressed in the head primordium. It has also been suggested that the affinity of Bcd-binding sites in the promoters of Bcd target genes determines the posterior extent of their expression (the Gene X model). However, both these hypotheses remain untested. Here, we show that a small regulatory region upstream of the cephalic gap gene orthodenticle (otd) is sufficient to recapitulate early otd expression in the head primordium. This region contains two control elements, each capable of driving otd-like expression. The first element has consensus Bcd target sites that bind Bcd in vitro and are necessary for head-specific expression. As predicted by the Gene X model, this element has a relatively low affinity for Bcd. Surprisingly, the second regulatory element has no Bcd sites. Instead, it contains a repeated sequence motif similar to a regulatory element found in the promoters of otd-related genes in vertebrates. Our study is the first demonstration that a cephalic gap gene is directly regulated by Bcd. However, it also shows that zygotic gene expression can be targeted to the head primordium without direct Bcd regulation.

Animals↗
PubMed1998

[A study on the correlation between the activity of 72,000 type IV collagenase and the metastatic potential of cancer cells].

OBJECTIVE: To evaluate the enzyme activity of 72,000 type IV collagenase and its relationship with the metastatic potential of cancer cells. METHODS: The levels of secreted 72,000 type IV collagenase in the conditioned media of five human cancer cell lines with different metastatic potential and a normal lung fibroblast strain treated with cancer cell culture media were examined by gelatin zymography and densitometric analysis. RESULTS: The levels of 72,000 type IV collagenase secreted by cancer cells with high metastatic potential (PG, WM451 and WM983a) were higher than those secreted by cancer cells with low metastatic potential (PAa and WM35). In the conditioned media of fibroblasts which were treated with the culture media of PG and WM451, enhanced levels of activation were observed. CONCLUSION: The secretion of 72,000 type IV collagenase is closely correlated to the metastatic potential of cancer cells. The cancer cells with high metastatic potential may possibly through certain soluble mediators stimulate normal fibroblasts to activate 72,000 type IV procollagenase.

Adenocarcinoma↗
PubMed1998

[Investigation of retroviral infection in human acute myeloid leukemia].

OBJECTIVE: To explore the potentiality of retroviral etiology in human acute myeloid leukemia (AML). METHODS: Cell culture techniques, direct immunogold silver staining(D-IGSS), reverse transcriptase (RT)assay, XC syncytium assay, and electron microscopy were employed to evaluate retrovirus associated antigens (RVAAgs), RT activities, CPE, and virus particles of both leukemic cells and normal hematopoietic cells. RESULTS: RVAAgs were detected by D-IGSS in 50.0% of fresh AML cell samples and 87.5% of cultured AML samples. RT assay showed that RVAAg-positive samples from 14 cases simultaneously expressed RT activities, and XC syncytium assay also revealed positive results. Electron microscopy demonstrated typical type C retrovirus particles at various maturation in 75% of cultured leukemic cell samples. In contrast, neither RVAAgs and RT activity nor syncytium and virus particles were detected in normal controls. CONCLUSIONS: AML cells harbor the entire genome(s) of retrovirus(es), which could release into extracellular spaces in intact particles via budding from the target cells stimulated in vitro by appropriate RV inducing agents. The exact relationship between these viruses and AML etiology is uncertain and needs further study.

Adult↗
PubMed1998

[Effect of T-lymphocytes on hematopoietic progenitors in patients with paroxysmal nocturnal hemoglobinuria].

OBJECTIVE: To study the effect of T-lymphocytes on hematopoietic progenitors in patients with paroxysmal nocturnal hemoglobinuria (PNH). METHODS: Phytohemagglutinin-stimulating T-lymphocytes conditioned medium(PHA-TCM) prepared from PNH(PHA-TCM-PNH) and normal blood(PHA-TCM-N) was added to the cultures of PNH or normal CFU-GM and BFU-E. RESULTS: In cultures containing PHA-TCM-PNH prepared from newly diagnosed PNH patients, the yields of CFU-GM and BFU-E from either PNH or normal bone marrow were reduced more than they did in cultures containing PHA-TCM-N; but in cultures containing PHA-TCM-PNH prepared from PNH patients in remission, they were normal. CONCLUSION: T-lymphocytes from newly diagnosed PNH patients exerts an inhibitory effect on the in vitro growth of CFU-GM and BFU-E.

Adolescent↗
PubMed1998

[The valuation of paranasal sinus coronal CT scanning in endoscopy sinus surgery].

We applied coronal CT scanning of paranasal sinus to 260 patients with chronic sinusitis before they were performed endoscopy sinus surgery. The correct diagnostic rate was 99.2% in our study. The positive findings of CT were compared with that from normal person. By analyzing, we consider that coronal CT scanning can clearly reveal various anatomic variation for all sinuses, also, it is valuable in evaluating the difficulties of endoscopic sinus surgery and preventing dangerous operative complications.

Adolescent↗